When the sun runs out of H, it starts collapsing and starts burning He (into C), at which time it expands and becomes a red giant (burning up the earth in the process). After running out of He, it collapses into a white dwarf.

Yeah i read that in a few billion years, the sun will expand 2000 times its normal size, engulfing Mercury and Venus. Even if it does not engulf Earth, its light rays will vaporize our oceans and life will end.
Mathman has the other part correct. I'm not so sure if what i just wrote is 100% correct, because i haven't read the part where it explains about how the Solar System will end in this book that i have.

Originally posted by Andy yea but before that a race of evil aliens might come along and destroy the entire solar system.

lmao!
Well that could happen, yes.....they'd surround the entire solar system, coz they'll probably think that we'd be able to escape, but they're wrong, no we cannot escape coz of our technology, how low it is teehee!
They'd attach a bomb to each planet and its moons. A bomb that explodes so monstrously, that it expands 5000 times larger than the sun hehehehe